The function ch_jarvis_march generates the counterclockwise sequence of extreme points from a given set of input points that line between two input points.
#include <CGAL/ch_jarvis.h>
 

 
generates the counterclockwise subsequence of
extreme points between start_p and stop_p of the
points in the range [first,beyond), starting at
position result with point start_p. The last point
generated is the point preceding stop_p in the
counterclockwise order of extreme points.

The default traits class Default_traits is the kernel in which the type ForwardIterator::value_type is defined.
CGAL::ch_jarvis
CGAL::lower_hull_points_2
CGAL::upper_hull_points_2
The function uses the Jarvis march (giftwrapping) algorithm [Jar73]. This algorithm requires $$O(n h) time in the worst case for $$n input points with $$h extreme points.